1. Field of the Invention
The present invention relates to a substrate processing apparatus and a method of manufacturing a semiconductor device.
For example, the present invention may be effectively applied to a thermal treatment apparatus (furnace) configured to perform a thermal treatment process such as a film forming, annealing, oxidation, diffusion, or reflow process to form an oxide layer, a metal layer, or a semiconductor layer on a semiconductor wafer (hereinafter, referred to as a wafer) for forming a semiconductor integrated circuit device (hereinafter, referred to as an IC).
2. Description of the Prior Art
In a method of manufacturing an IC, a thermal treatment apparatus such as a batch type vertical hot-wall chemical vapor deposition (CVD) apparatus is widely used to deposit a material such as silicon nitride (Si3N4), silicon oxide (SiOx), and polysilicon on a wafer.
The hatch type vertical hot-wall CVD apparatus (hereinafter, referred to a CVD apparatus) includes: an outer tube; an inner tube installed inside the outer tube to form a process chamber; a heating device (heater) configured to heat the inside of the outer tube; a manifold on which the outer and inner tubes are placed and to which an exhaust pipe and a gas introducing pipe are connected for exhausting the process chamber and supplying gas to the process chamber; and a boat configured to hold a plurality of vertically arranged wafers and be loaded into the process chamber.
When the boat in which a plurality of wafers are held is loaded into the process chamber through a lower furnace throat, a film-forming gas is supplied to the process chamber through the gas introducing pipe, and at the same time, the process chamber is heated by the heating device, so that CVD layers can be deposited on the wafers.
Such a conventional CVD apparatus, for example, a CVD apparatus disclosed in Patent Document 1, includes a manifold (furnace throat flange) made of a metal.
Since the metallic manifold has a thin plate thickness and low heat capacity, heat can be easily dissipated to the outside of a furnace throat.
[Patent Document 1] Japanese Unexamined Patent Application Publication No. 2002-334868
However, such a CVD apparatus including a metallic manifold has a problem in that the metallic manifold is corroded by reaction products, which are generated from reaction gas and cleaning gas and attached to the metallic manifold.
Moreover, as the size of ICs reduces, metal emission from the metallic manifold of the CVD apparatus causes other problems.